International Conferences and Workshops

1. "Time Crystals and Time Operators in Ring Systems",
   K. Nakatsugawa, T. Fujii, A. Saxena & S. Tanda,
   Time Crystals and Related Phenomena,
   Sept. 4, 2019, Jagiellonian University, Kraków, Poland.
2. "Topological operators: New concept of real-space topology for time crystal, time operators, and quantum measurement",
   Keiji Nakatsugawa, Toshiyuki Fujii, Avadh B. Saxena, Koichu Ichimura & Satoshi Tanda,
   33rd Summer Conference on Topology and its Applications,
   July 18, 2018, Bowling Green, Kentucky, USA.


3. "Quantum Time Crystal by Decoherence in Ring Systems",
   Keiji Nakatsugawa, Toshiyuki Fujii & Satoshi Tanda,
   APS March Meeting 2018,
   March 5, 2018, Los Angeles Convention Center, Los Angeles, California, USA.


4. (INVITED) "Quantum Time Crystal By Decoherence in Ring Crystals (Topological Systems)",
   Keiji Nakatsugawa, Toshiyuki Fujii & Satoshi Tanda,
   FY 2017 CNLS Colloquium series,
   March 21, 2017, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.


5. "Quantum Time Crystal by Decoherence in Incommensurate Charge Density Wave Ring",
   Keiji Nakatsugawa, Toshiyuki Fujii & Satoshi Tanda,
   APS March Meeting 2017,
   March 15, 2017, Ernest N. Morial Convention Center, New Orlearns, Lousiana, USA.

Conferences and Workshops in Japan

1. (INVITED) "Time operators and time crystals in ring systems",
   Keiji Nakatsugawa, Toshiyuki Fujii, Avadh B. Saxena & Satoshi Tanda,
   Mathematical Aspects of Quantum Fields and Related Topics,
   June 28, 2019, Kyoto University, Kyoto, Japan.


2. "Time Operators and Time Crystals",
   Keiji Nakatsugawa, Toshiyuki Fujii, Avadh B. Saxena & Satoshi Tanda,
   Mathematical Society of Japan Spring Meeting 2019,
   March 17, 2019, Tokyo Institute of Technology, Tokyo, Japan


3. "Charge Density Wave in Monolayer: The Nakanishi-Shiba Model Revisited",
   Keiji Nakatsugawa, Satoshi Tanda, Tatsuhiko N. Ikeda,
   JPS Annual (74th) Meeting,
   March 15, 2019, Kyushu University, Fukuoka, Japan.


4. "Time Operators and Time Crystals",
   Keiji Nakatsugawa, Toshiyuki Fujii, Avadh B. Saxena & Satoshi Tanda,
   JPS Annual (74 th) Meeting,
   March 14, 2019, Kyushu University, Fukuoka, Japan.


5. (Invited) "Time Operators and Time Crystals: Self-Adjointness by Topology Change",
   Keiji Nakatsugawa, Toshiyuki Fujii, Avadh B. Saxena & Satoshi Tanda,
   Workshop on Non-Hermitian Systems and Optical Experiments (translated from Japanese),
   March 1, 2019, Hokkaido University, Sapporo, Japan.


6. "Quantum Time Crystal by Decoherence",
   Keiji Nakatsugawa, Toshiyuki Fujii & Satoshi Tanda,
   JPS Annual (73th) Meeting,
   March 23, 2018, Tokyo University of Schence, Noda, Chiba, Japan.


7. 「有限系におけるquantum space-time crystal」,
   Keiji Nakatsugawa, Toshiyuki Fujii & Satoshi Tanda,
   JPS Annual (71th) Meeting,
   March 16, 2016, Tohoku Gakuin University Izumi-Ku, Sendai, Japan.


8. 「非整合電荷密度波リングにおけるQuantaum Space-Time Crystal」,
   Keiji Nakatsugawa, Toru Matsuura, Toshiyuki Fujii, & Satoshi Tanda, JPS Annual (70th) Meeting,
   March 22, 2015, Waseda University, Shinjuku-ku, Tokyo, Japan.